Devices for evacuation of impurities forming in welding processes

ABSTRACT

A device for evacuation of impurities forming in welding processes with supply of protective gas comprises a tube rotatably mounted on the welding tool and surrounding said tool clearance, said tube being provided at its front end portion with an intake opening and having a laterally projecting coupling piece which serves as a handle and is connected to a suction hose.

United States Paten 1191 1111 3,775,587

Lindkvist Nov. 27, 1973 [54] DEVICES FOR EVACUATION 0F 1 3,514,5675/1970 Strang 219/75 IMPURITIES FORMING IN WELDING FOREIGN PATENTS ORAPPLICATIONS PROCESSES 1,526,305 5/1968 France....- 219/136 [76]Inventor: ldlrlrlliekglsstzyligzplralsvagen OTHER PUBLICATIONS Mishler,Monroe & Martin, Development of Special [22] Flled: 1972 Welding NozzleConfiguration, Sept. 1962, Battelle [21] Appl. No.: 278,761 Memoriallnstitute, pp. l28.

Primary Examiner-Bruce A. Reynolds [30] Foreign Application Pr orityData Atmmey John Lezdey et a1 Aug. 9, 1971 Sweden 10163/71 52 vs. C]219/130, 219/70, 2l9/136 fBSTRACT 51 Int. Cl. B23k 9/32 A device forevacuaflon of impurities forming in weld- [58] Field of Search 219/130,136,74, ing Processes with pp of Protective gas comprises 219/75 70 atube rotatably mounted on the welding tool and surrounding said toolclearance, said tube being provided [56] Refe cig d at its front endportion with an intake opening and UNITED STATES PATENTS having alaterally projecting coupling piece which 3 654 421 4/1972 St t 1 2l9/70serves as a handle and is connected to a suction hose.

5 5 ree man 3,524,038 8/1970 OKell 219/70 7 Claims, 2 Drawing Figures I(1/ 6 ,5 76 1 1 z a l 26 74 "DEVICES?FOR'EVEXCUATION.OFIIMPURITIESFFORMING IN 'WEILDING' PROCESSES- This invention'relates to radevicefor-evacuation of smoke and other airborne impurities forming at the'useof -weldingrapparatuses:equipped with means for suptplyingfprotectivegas and including .a central welding wiregguidezenclosed'bylanozzleejecting the protective gas surrounding .the weld.

zln 'welding'processes'where use-is made of a protectiveggassurrounding. the weld it :is imperative that there is man unimpeded flowof "protective .1gas towards the weld. sothat the :gas willcover theweld to the necessary -extent. Protective tgas-is often used in carryingout work .onsurface. treated materials and in welding alloyed orothermetalsxemitting'obnoxious substances and gases,

.andit was early"realize'cl that the' problem of carrying zaway welding'smokerhad' torbe-solved. 'As certain exiperimentshave shown one mightunder favourable con- :ditions -:employ .-.a relatively :simpleevacuating device whichistplacedxadjacent'the weld and sucks away 'smokeandisoli'd'tparticles therefrom. However, it has .ibeenlfoun'd thatwhenzuse is'i'madeof welding equip- .ment'having'means for supplyingprotectivetgas itis of thezutmost importancer-to veryexactly dimensionthe vacuum of and the: rate of'flow in the evacuating device becausetheprotective :gas around the weld will otherwisebedisturbe'd and-sevencarried along. lt'has been :suggested to solvetthissrproblem byincreasing the-supply..an'd/orthe-pressure ofi'the protective .gas butthis is not an acceptable solution forveconomical reasons. In

welding work pieces oftcomplicated configuration it is -not"eitherpossible always to place separate evacuating devices sufficiently :closeto the weld."Moreover,such

an evacuating device constantlyihas to be moved as work, proceeds and;if I the welding operator wishes to safeguard an uninterruptedevacuation of welding smoke and'like obnoxiousgases he often has tointerrruptfhiswork and adjustthe device.Different types of work requiredifferent'pressures of thejprotective gas ."andas it isv important foreconomical reasons thatthe gas consumption iskept as low as possible,the capacity of the evacuating device must becarefully adjusted forneach'worki. In a'separate device of this type thiswill not 'be'feasible, and to .ensurethat the protective gas is not impaired inany-way, as a ruletoo large a quantity of *protectiveggas is allowed'toescape orso low a vacuum is-employedthat'theresulting evacuation isunsatisfac- 'tory.

0ne object ofthe present invention is to provide a device whichindependently of the configuration of the workpiece and'the ipressure ofthe protective gas supplied alwaysensuresan effective evacuation ofthe-im- ;purities formingin welding operations. According'to ;bodimentof the device;

'PICL Z partly in sectiomshows a'slightly modified'embodiment as seen-from 'blow.

The welding apparatus illustrated in the drawing comprises a'handle '1to the rear end of which there is fixedly connected a hose 2 having aguide passage for the welding wire and serving as a conduit forsupplying the protective gas. The handlel merges in the tool 3 properwhich comprises a nozzle portion through the centre of which extends aguide 4 for the welding wire 5. The protective gas is thus discharged atthe front end of the tool 3, thereby forming a protective gas cushionaround the are at the welding wire.

In the'embodiment illustrated in FIG. 1, thedevice for evacuation ofwelding smoke and other airborne particles from the weld includes a tube6 which is rotatably and movably carried by a' supporting ring 7 mountedaround the tool 3 at the handle 1. To permit rotation'of the tube andsimultaneously ensure retention thereof in longitudinal direction thesurface of en- 'gagement 8 of the supporting ring may be formed withprjections 9 which engage in annular grooves-l0 in the inner surface ofthe tube end. A transverse groove 11 permits moving the tube intovarious positions and also dismounting thereof.

A sleeve '12 is mounted for rotation about the tube 6 and has aconnecting socket 14 disposed at a recess 13 and having the curvedcoupling piece 15 rotatably mounted thereon. The interconnection of thesocket and the coupling piece can be realized in the same way as that ofthe tube and the supporting ring. The coupling piece 15 in turn isadapted for interconnection with the suction hose 16 which is coupled toa suction system in which an approximately constant vacuum prevails.

A recess 17 is formed in the tube 6. It is preferably at least equallylarge in the peripheral sense as the recess13 in the sleeve 12, and byrotation of the sleeve 12 through a small or large angle the recess 17can be caused-wholly or partly to overlap the recess 13 in the sleeve.Byadjustingthe sleeve 12 into different positions-with respect to the tube6 the flow from the tube 6 to the hose can be regulated or throttled.

To prevent that a relative position set between the tube 6'and thesleeve 12 is altered for instance when the coupling piece because of theconfiguration of the work piece has to be swung from one side of thetool to the other some kind of locking mechanism should be arrangedbetween the tube 6 andthe sleeve 12. In the embodiment illustrated astopring 27 is secured ahead of the sleeve to the tube 6 and a boss 28is provided on the sleeve 12. In the edge of the ring 27 facing thesleeve l2'there are formed several notches 29 which correspond todifferent throttling positions. A resilient means in the form of aspring 30 or a rubber ring is disposed rearwardly of the sleeve 12 sothat the sleeve can be shifted rearwardly against the action of saidresilient means and so turned that the boss 28 will be placed opposite adesired notch 29. However, said locking mechanism can be given any otherdesired design, For instance, a ring exerting appropriate friction canbe provided between the sleeve and the tube.

A suction nozzle 18 is arranged at the front end of the tube 6. In theembodiment illustrated in FIG. 1 said nozzle is formed by an outwardlyflared portion 19 which may be integral with the tube 6. In certaincircumstances it may be difficult with the use of a flared nozzle to getsufficiently close to the weld. In that case use can be made of thenozzle illustrated in FIG. 2. The latter nozzle which is adapted topermit being used nozzle also on planar surfaces the nozzle has an outerrotary ring 21 which when welding is effected in corners can be set inparallel with the part 20, but which is otherwise rotated through 90,thereby laterally screening the apertures formed in the part 20. Thenozzle having the ring 21 can of course be given such a configurationthat the outer portions thereof extend obliquely outwardly.

When welding smoke and obnoxious gases are evacuated in work whereuse'is made of a low pressure of the protective gas it might happen thatthe protective gas envelope around the weld is disturbed and the qualityof the weld is jeopardized. To obviate this the tool can be providedwith a screen ring 22 placed just behind the nozzle aperture thereof,said screen ring having the shape illustrated in FIG. 1 or any othershape warranted by the specific conditions prevailing at the weld. Theprovision of the screen ring 22 will eliminate the risk of theprotective gas envelope around the weld being disturbed or carried away.

When welding operations are made at perpendicular surfaces it mayhappen, particularly if theevacuation has to beheavily throttled becauseof a low protective gas pressure, that the thermal lifting force of thewelding gases exceeds and counteracts the force exerted by theevacuating device so that at least part of the welding gases rise andare not caught by the nozzle 18 of the tube 6. To prevent this, aspecific evacuation tube 23 is arranged in the embodiment according toFIG. 1. As shown, the tube 23 in inoperative position is fully pushedinto the coupling piece 15 and projects through an opening 24 having aflange which is adapted to serve as a guide. The tube 23 is open at therear end and has at the front end a cover-like part 25 which in theretracted position of the tube prevents air from being sucked thereinto.Adjacent the front end, the tube 23 is cut such that an elongatedopening 26 is formed. In the position of use indicated by dash lines itis shown how the opening 26 when welding is effected will be situatedabovethe weld so that it is able to catch the welding smoke. v

The aforementioned evacuating tube 23 may be incorporated in thecomplete equipment of the evacuating device, but it may also constitutea special attachment together with the coupling piece which isspecifically conformed for this purpose.

- It should finally be mentioned that owing to its configuration theevacuating device to a not inconsiderable extent facilitates handling ofthe welding tool.

In welding tools devoid of evacuating device the operator is oftenforced to grasp the tool by the insulating handle which is at arelatively large distance from the front end of the tool. Even if hemakes use of both hands the work is very tiresome. Considering that theevacuating device is spaced from the tool proper and besides is cooledto some extent by the air sucked therethrough, the tube and the sleeveand/or the coupling piece can be utilized as an additional handle, whichgives an improved balance of the tool and less strenuous holdingthereof.

What I claim and desire to secure by Letters Patent 1. A device forevacuation of smoke and other airborne impurities formed during the useof welding apparatus having means for supplying a protective gassurrounding a central welding wire guide enclosed by a nozzle forejecting the protective gas around the weld, said device comprising anevacuating tube rotatably mounted on and surrounding the welding tooland spaced therefrom, said tube being provided at its front end portionwith an intake opening, a coupling element mounted on and projectinglaterally from said tube, a suction hose connected to said couplingelement, said coupling element including a sleeve rotatably mounted onsaid tube, the circumferential wall of said tube and said sleeve beingprovided with corresponding openings therein whereby the passage formedby said combined openings leading to the suction hose may be regulatedby relative rotation of one of said evacuation tube and said sleeve withrespect to the other.

2. A device as claimed in claim 1 and further comprising means forlocking the sleeve in a predetermined angular position with respect tosaid tube.

3. A device as claimed in claim 1 and further comprising a conicalscreen ring mounted on the nozzle for ejecting the protective gas at aposition adjacent the intake opening of said evacuating tube.

4. A device as claimed in claim 1 wherein the intake opening of saidevacuation tube comprises two concentric, mutually rotatable, tube-likeelements each having oblique, wedge-shaped recesses in the outercircumference thereof, whereby, when aligned, said concentric elementspermit welding in corners and when offset, prevent excess air fromentering said evacuation tube.

5. A device as claimed in claim 1 and further comprising telescopicmeans mounted on said coupling element for selectively withdrawingairborne impurities laterally of the intake opening of said evacuatingtube.

6. A device as claimed in claim 5 wherein said telescopic means isprovided with an intake opening adjacent its outer end, said meanstelescoping longitudinallyof the axis of the welding tool.

7. A device as claimed in claim 1, wherein said coupling element isrotatably mounted on said evacuation tube.

1. A device for evacuation of smoke and other airborne impurities formedduring the use of welding apparatus having means for supplying aprotective gas surrounding a central welding wire guide enclosed by anozzle for ejecting the protective gas around the weld, said devicecomprising an evacuating tube rotatably mounted on and surrounding thewelding tool and spaced therefrom, said tube being provided at its frontend portion with an intake opening, a coupling element mounted on andprojecting laterally from said tube, a suction hose connected to saidcoupling element, said coupling element including a sleeve rotatablymountEd on said tube, the circumferential wall of said tube and saidsleeve being provided with corresponding openings therein whereby thepassage formed by said combined openings leading to the suction hose maybe regulated by relative rotation of one of said evacuation tube andsaid sleeve with respect to the other.
 2. A device as claimed in claim 1and further comprising means for locking the sleeve in a predeterminedangular position with respect to said tube.
 3. A device as claimed inclaim 1 and further comprising a conical screen ring mounted on thenozzle for ejecting the protective gas at a position adjacent the intakeopening of said evacuating tube.
 4. A device as claimed in claim 1wherein the intake opening of said evacuation tube comprises twoconcentric, mutually rotatable, tube-like elements each having oblique,wedge-shaped recesses in the outer circumference thereof, whereby, whenaligned, said concentric elements permit welding in corners and whenoffset, prevent excess air from entering said evacuation tube.
 5. Adevice as claimed in claim 1 and further comprising telescopic meansmounted on said coupling element for selectively withdrawing airborneimpurities laterally of the intake opening of said evacuating tube.
 6. Adevice as claimed in claim 5 wherein said telescopic means is providedwith an intake opening adjacent its outer end, said means telescopinglongitudinally of the axis of the welding tool.
 7. A device as claimedin claim 1, wherein said coupling element is rotatably mounted on saidevacuation tube.